/* Copyright (C) 2008  Romolo Camplani, Marco Fortunato, Marco Marelli, Guido Rota, Fabio A. Schreiber et al.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */
package org.dei.perla.parser.expressions;

/**
 * @author Stefano Vettor
 */
public class NodeIsNull extends NodeLogicalOperation {

	private boolean notFlag;
	
	/**
	 * @param parFirst
	 * @param parSecond
	 */
	public NodeIsNull(Node parFirst, boolean parNotFlag) {
		super(parFirst, null);
		this.notFlag = parNotFlag;
	}
	
	public Constant getResult() throws ConstantCreationException, ConstantCastException, OperationNotSupportedException, DivisionByZeroException {
		if (notFlag) {
			ConstantLogic parRet = new ConstantLogic(this.getFirstNode().getResult().isNull());
			return parRet.not();
		}
		else
			return new ConstantLogic(this.getFirstNode().getResult().isNull());
	}
	
	public Class<? extends Object> getResultType() throws OperationNotSupportedException {
		return ConstantLogic.class;
	}
	
	public String toString()
	{
		if (notFlag)
			return this.getFirstNode().toString() + " IS NOT NULL";
		else
			return this.getFirstNode().toString() + " IS NULL";
	}

}
